The present disclosure relates to a protection system against reverse battery connection which is connected to a battery in an electric vehicle.
Recently, environmentally-friendly vehicles, specifically, electric vehicles attract attention due to environmental issues.
Some of electronic components for a vehicle, which are used for the purpose of charging, include a high-voltage battery, an on-board charger (OBC) for charging the high-voltage battery, a low-battery battery, a load device, a low-voltage DC-DC converter (LDC) and the like.
The LDC or OBC serves to convert a voltage of the high-voltage battery into a low voltage to charge the low-voltage battery or transfer power to the load device.
The LDC charges the low-voltage battery with such electric energy and transfers power to the load device.
Various electronic components in conventional vehicles other than electric vehicles are operated using a low-power battery (e.g., a 12V battery).
In the case of such electronic components, reverse connection may occur due to replacement of a low-power battery or an operational error, and may cause a short circuit between the electronic components and the low-power battery, so that circuits of the electronic components may be damaged.
Typically, a high-voltage protection diode against reverse connection, a transient voltage suppressor or a fuse is used to protect a circuit when a low-power battery is reversely connected.
In particular, a diode as illustrated in FIG. 1A is typically used. Such a diode prevents a circuit from being damaged due to reverse connection by blocking a current of an entire circuit if a low-power battery is reversely connected.
However, in the case where a battery is connected in a normal forward direction as illustrated in FIG. 1B, an electric efficiency of an entire system is reduced due to conduction loss that occurs in a diode of a protection circuit against reverse connection.
Furthermore, in the case of using a high-capacity output electronic component of an electric vehicle, a short circuit may occur between the electronic component and the diode when a low-power battery is reversely connected, so that a circuit may be damaged. Moreover, in the case of the OBC or LDC, a current of an output terminal thereof flows towards a low-power battery, a diode is connected in the direction of the current, and a diode in a protection circuit against reverse connection is connected in a direction opposite to that of the diode positioned at the output terminal of the OBC or LDC. Therefore, a reverse connection preventing circuit employing a diode may not be applied to the OBC or LDC that is a high-capacity output electronic component.
The above-mentioned issue becomes more important as environmentally-friendly vehicles, most of which are driven with electric energy, attract more attention due to environmental issues. Therefore, it is necessary to develop a technology for preventing reverse connection of a battery in an electric vehicle or protecting a circuit when the battery is reversely connected.